One often overlooked aspect of terrarium care is terrarium lighting. Whether you are using natural lighting or relying on grow lights to keep terrarium plants happy and healthy, it is important to get this right. Without the right lighting, plant health can quickly deteriorate and both too much light and too little can cause a range of issues.
The importance of terrarium lighting
While the plants often recommended for growing in terraria are frequently tolerant of low light conditions, that does not mean that they can cope without any light at all.
It is important to consider the light requirements of the specific plants you wish to grow, and to make sure that you place your terrarium in a location where the lighting is neither too much nor too little, but in the ‘goldilocks zone’ and ‘just right’.
Natural light vs grow lights
The first thing to work out is whether you will provide the light plants need for photosynthesis with natural daylight, or with grow lights of some kind.
Natural daylight and LED grow lights can both provide the light that plants require, though of course some plants will require more light than others. So when positioning grow lights or choosing a location where the terrarium is in a location with sufficient sun, you need to know which plants you wish to grow.
Most common terrarium plants require a position in bright but indirect light, sometimes also referred to as bright but filtered light. Understanding how to create those conditions is important when growing many tropical houseplants, and many other terrarium plants besides.
Positioning a terrarium for natural light
To get those ‘goldilocks zone’ conditions for terrarium plants that like bright but indirect light, you need to think carefully about where your terrarium is placed.
Position your terrarium in a location where they are in a fairly bright situation but out of direct sun which can cause problems like leaf scorch for many plants. Usually, indoors, this means looking carefully at which direction the windows in a room are facing.
How much light a home receives throughout each day and throughout the year will of course depend to a great extent on the home’s location, as well as the glazed areas and other elements of the home’s design.
Generally speaking however, in the northern hemisphere, we can see that south facing windows get the most direct sunlight, while north facing ones have the least. East facing windows get the sun in the morning, while west facing ones get the sun in the afternoon.
For bright but indirect light, a terrarium is best placed near a north or east facing window. South and west facing ones can get too hot and bright in many instances. However, in a room with south or west facing windows, a terrarium might simply be placed further away from the window through which the light is entering the space.
Choosing grow lights for a terrarium
Many terrarium plants can cope just fine with the natural light levels in most homes, when they are given an appropriate location. But there are some plants that will require a little more light than it is easy for temperate climate homes (especially ones located furthest north) to provide – particularly through the darker winter months.
This is when grow lights can come in handy. LED grow lights are now widely available, relatively affordable, and cheaper to run than the older fluorescent type.
Different colours of lights can be purchased but for most terrarium plants, you will use white, full-spectrum type LEDs. It is only experienced growers who may wish to delve deeper into wavelengths of light and how to optimise the growth of specific plants.
When choosing grow lights for your terrarium, you will of course need to consider how these will be affixed or supported above your plants – close enough but not too close to them.
A single ‘daylight lamp’ might suit a small terrarium jar or bowl, while larger aquarium style terraria might suit strip grow lights of some kind. Be sure to consider the size and shape of your terrarium when making your grow light choice.
Using grow lights for a terrarium
If you are using grow lights for a terrarium then there are a few additional things to bear in mind.
One key thing to think about is whether the lights you have chosen are emitting much heat. If they do, this is something to be aware of, as it may affect the function of a terrarium and the plants growing within it.
In most cases, it will be easy enough to switch on and off grow lights above terraria when required. However, you may wish to consider adding timers to the system so that the lights come on when needed, and yet are switched off when no longer required without you having to remember each time.
Terrarium lighting need not be complex. But it is something about which you can learn a lot more if you are interested in the subject. The right lighting will not only keep plants happy and healthy but can also improve how your terrarium looks within your home.